1. Technical Field:
The present invention relates generally to a clock generation system and in particular to a method and apparatus for multiplying the frequency of a clock signal.
2. Description of the Related Art:
It is known that signals that are ninety degrees out of phase can be XORed together to create a new signal that is twice the frequency of the original signal XORed. Turning to FIG. 1, a schematic diagram of a clock doubling circuit known in the art is illustrated. Circuit 100 is an XOR gate 102 that receives input clock signals 104 and 106. Input clock signal 104 is ninety degrees out of phase with input clock signal 106. XOR gate 102 XORs together input clock signals 104 and 106 to generate output clock signal 108, which is twice the frequency of the input signals. Both input clock signal 104 and input clock signal 106 have the same frequency. As mentioned above, the difficulty in producing output clock signal 108 with a frequency twice that of the input clock signals lies in producing input clock signals that are ninety degrees out of phase. Therefore, it would be advantageous to have a method and apparatus for doubling the frequency of a signal while reducing the difficulty in generating the clock signals that are ninety degrees out of phase.